Spray-gun head



Jan. 3, 1928.

. M. J. BINKS SPRAY GUN HEAD Filed Jan.'7. 1927 Patented Jan. 3, 1928i.

UNITED STATES rasant Param carica.

MELVIN J. BINKS, OIE1 OAK PAR-K, ILLINOIS, ASSIGNOR TO BINKS SPRAY EQUIEMENT C0., OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

SPRAY-GUN HEAD.

Application led January 7, 192?. Serial No. 159,651.

My invention relates to head constructions for spray appliances of the type in which compressed air is employed both for projecting` an annular -sheath of air around the projected stream of liquid and for projecting converging jets of air against the resulting air-sheathed stream of liquid.

In appliances of this class-coinmonly used in the formv of so called spray gunsthe proper iattening of the spray and the uniformity of the spray depend largely on two points. One is an accurate concentricity of the head parts between which the annular sheath of air is projected and an axial alining of these parts, as this air sheath would otherwise vary in thickness at different points in any 0iven transverse section, thereby seriously aecting the distribution of the intensity in the spray and the shape of the latter. The other point is the accurate directing of the converging air jet-s which fiatten the spray and which cooperate with the annular sheath of air in atomizing the stream of liquid. rlhe ports for these converging air jets are usually formed in a single head part symmetrically with the axis of the latter, hence the attaining of this point means an accurate alining of the axis of this head part with the axis of the annular air sheath and also with the axis of the projected stream. of liquid.

Moreover, the user of such a spray gun should be able to shift the plane along which the spray is iiattened, so that-with the liquid stream projected horizontally-d this plane may be vertical, horizontal or in intermediate positions. The provisions for such a change in the position of the flattening plane should not affect the air supply either for the converging air jets, and particularly should not permit these jets to be shut off, since the absence of air issuing from them may cause the converging air ports to be clogged by the coating material rebounding from the object which is being coated. Hence any arrangement which allows the converging air jets to be throttled or shut-o-even momentarily-is undesirable in practice.

My present invention aims to provide an unusually simple, and easily manipulated spray gun head construction which will attain the above objects, which will not require accuracy of manufacture beyond that attainable in good brass finishing shops,

and which can easily be cleaned when necessary. Further and also more detailed objects will appear from the following specification. and from the accompanying drawings, 1n which -Fig. l is a central, vertical and longitudinal section through the forward portions of a. spray gun embodying my invention.

Fig. 2 is a front elevation of the same parts.

. Fig. 3 is an enlarged side elevation of the liquid nozzle of the embodiment of Fig. l.

Fig. 4 is a front elevation of the liquid nozzle.

F ig. 5 is a section similar to the forward portion of Fig. l, but showing another embodiment, namely one in which the annular groove is in the bore of the air nozzle.

Fig. 6 is a rear elevation of the air nozzle of Fig. 5.

Referring first to Figs. l to 4 inclusive, these show forward parts of a spray gun in which the body l has `an exteriorly threaded forward end portion lA projecting beyond an outwardly directed radial flange 2. The gun body l has a liquid supply passage 3 substantially coaxial with the thread on its Gli projecting end 1A, to which passage liquid is supplied through an inlet passage 4, and the gun body also has an air passage 5 which opens through the forward face of the said projecting end.

Projecting forwardly beyond the said face and preferably detachable from the gun body is a liquid nozzle 6 which has its bore 7 in substantially axial alinement with the liquid supply ypassage 3, this bore having its forward outlet portion 7A contracted in diameter to form a small-diametered port for discharging the initially cylindrical stream of liquid. To secure the liquid nozzle to the gun body, I preferably provide this with a rear end threaded into the body near the forward end of the supply passage and flare the forward end of that passage to fit a rearwardly tapering part 8 of the liquid nozzle.-

The discharge end of the liquid nozzle, through which the small diametered port 7A extends is cylindrical and relatively small in diameter, so as to afford a thin annular wall around this port. Behind this cylindrical part, the liquid nozzle has as its exterior a generally frustro-conical and rearwardly flaring surface and desirably has a thin lill@ polygonal `portion 9 at the rear end of this tapering part, to be gripped by a wrench in screwing the said nozzle to the gun body so that its rearwardly tapering part 8 will afford a tight seal. However, the parts are proportioned so that even this polygonal portion 9 is spaced forwardly from the forward face of the body end portion 1A when the nozzle is tightly connected to the body. As a companion to the liquid nozzle, I provide a cap-like air nozzle having a bore which includes a generally frustro-conical and forwardly tapering portion fitting the said rearwardly flaring surface of the liquid nozzle, with this bore portion leading to a relatively short cylindrical outlet 10 which is slightly larger in diameter than the cylindrical tip of the liquid nozzle. The air nozzle has its bore enlarged back of its said tapering portion and interiorly threaded to afford a somewhat loose attachment to the male thread on the forward end portion of the gun body, and alsoV has diametrically op'- posite discharge passages extending from its forward end to its said tapering bore portion.

Each yof these discharge passages includes a straight outlet bore 11 inclined forwardly toward the 'axis of the air nozzle and a larger diametered bore 12 leading to the rear end of the bore 11 from the tapering portion of the bore of the air nozzle. To supply air both to these discharge passages and to the annular port between 'the tip of the liquid nozzle and the outlet bore portion 10 of the air nozzle, I provide longitudinal Grooves eX- tending along the juncture of the intertitting tapering surfaces of the liquid nozzle and the air nozzle, such as grooves 13 formed in the liquid nozzle. Then I also provide one of these nozzles with an annular groove ad- `jacent to these tapering surfaces and openlng into both of the discharge passage bores l12, such as a groove 14 formed on the liquid nozzle and intercepting all of the longitudinal grooves 13.

With the air nozzle screwed upon the body as shown in Fig. 1, the longitudinal grooves 13 (here shown as four in number) all connect the annular air outlet around the tip of the vliquid nozzle. with the air chamber 15 into which the air supply duct 5 opens, thereby insuring an ample air supply for discharging the annular sheath of air. Since the annular groove 14 intercepts these longitudinal grooves 13, the latter all supply air also to this annular groove and to the discharge passage bores 12 which open from the annular groove, and this annular groove can be formed relatively close to the forward end of the air 'chamber 15, so that the air travels for a quite short distance from that chamber in reaching the annular groove. Moreover,

- both this annular groove and each longitudinal groove 13 can be of much larger sectional area than each inclined' discharge bore 11, and the longitudinal grooves can be greater in number than the said discharge bores 11, so as to adord a substantially unthrottled supply of air to the bores 12 leading to the bores 11 and to do this regardless of the rotational position of the air nozzle with respect to the liquid nozzle.

Thus, while Fig. 1 shows the air nozzle in a position in which the inlet end of each bore 12 faces one longitudinal groove 13, the other two longitudinal grooves are also connected to the same bore 12 through the annular groove 14 which is so large in proportion to the two oulet ports 11 as to afford an ample air storage chamber. Hence the pressure of the air emitted by the ports 1l is practically undiminished when the air nozzle is rotated to bring its passages 12 out of alinement with any of the longitudinal grooves on the liquid nozzle, so that the flattening and the uniformity lof the resulting spray remains the same regardless of the position of the plane along which the spray is flattened. v

In manufacturing a spray gun with the above described head, ordinary machine shop accuracy will rarely afford an exactaxial alining of the interior and exterior threads on the front end of the. gun body, nor an exact axial alining of the liquid nozzle tip with the male thread on the rear end of the liquid nozzle, nor an exact axial alining of the outlet bore 10 of the air nozzle with the thread on the rear end of that nozzle. Consequently, such inaccuracies although minute in themselves might augment each other to bring the axes of the two nozzlesl out of alinement and likewise to bring the intersection of the axes of the ports 11 to a point outside the axis of the liquid nozzle. However, the tapering exterior surface portion of the liquid nozzle and the tapering bore portion of the air nozzle can easily be turned to counterpart tapers with a high degree of accuracy. Consequently, by seating the air nozzle on this tapering part of the liquid nozzle, I can insure the desired axial alinement of these two nozzles, pro vided that the threaded connection of the air nozzle to the gun body will permit the air nozzle to shift sufficiently. Hence I make the said threaded connection rather loose. Any escape of air between such loose threads will not be directed forwardly and hence would not affect the spray from the gun, but I desirably eliminate all such waste of air by providing the said radial flange 2 on the gun body and by interposing a compressible packing ring 16 between this flange and the rear end of the air nozzle.

However, while I have illustrated and d escribed lny invention in a desirable embo`diment, I do not wish to be limited to the above mentioned details of construction and lll) arrangement, since changes may obviously be made without departing either from the spirit of my invention or from the appended claims.

For example, the tapering surface portion of the liquid nozzle 6B may be left free from any annular groove, While the needed connections between the longitudinal grooves and the bores 12 of the air discharge passages can be made by a groove 17 formed in the interior of the air nozzle, from which the said bores 12 extend, as shown in Fig. 5. In this case, I may secure the air nozzle to the gun body by a ring 18 threaded on the body and having a contracted forward end engaging an outwardly directed flange 19 on the air nozzle.

I claim as my invention:

1. In a spray gun, a body, a liquid nozzle supported by and projecting forwardly from the said body, the liquid nozzle having a bore extending through it and the body having a liquid supply passage opening into the said bore; an air nozzle housing and iitted upon a part of the liquid nozzle forward of the body, the said interfitting parts ofthe two nozzles being along generally frustro-conical and forwardly tapering surfaces; the air nozzle having a central discharge outlet coaxial with its said tapering surface and having a pair of diametrically opposed discharge passages, each such discharge passage comprising a forward portion and a rear portion leading to the said forward portion from the said tapering surface, the forward portions of the two discharge passages having their axes intersecting at a point forward of the air nozzle and on the axis of the tapering surface of the latter; means securing the ai'r nozzle to the body and clamping the air nozzle upon the liquid nozzle, the said means being arranged to permit a limited shift-ing of the air iiozzle with respect to the body; the air nozzle having its bore formed to afford an air space forwardly of the gun body and.. the said body having an air supply passage opening into the said air space; one of the said nozzles having longitudinal grooves extending along its said tapering surface and connecting the said space with the space between the central discharge outlet of the air nozzle and the tip of the liquid nozzle, and one of the nozzles having an annular groove along its said surface opening to the rear portions of both of the said discharge passages.

2. In a spray nozzle, a liquid nozzle having a small diametered outlet end and a forwardly tapering exterior of generally frustroconical form behind its tip; an air nozzle having a tapering bore portion fitted `upon h the tapering exterior of the liquid nozzle and having its frontal bore portion freely surrounding the said tip, the air nozzle also having two diametrically opposite discharpm passages leading from its said bore portion to its front, the forward parts of the two discharge passages having their axes intersecting on the axis of the said bore portion forwardly of the air nozzle; the said nozzle assembly being provided with connecting passages extending along the said interiitting portions from the rear end-of the said frustro-conical portion of the liquid nozzle substantially to the 'fn-ntal bore portion of the air nozzle, the nozzle assembly also having an annular groove connecting the said connecting passages with the rear ends of the two discharge passages; and securing means rigidly holding the nozzles in their said interlitting relation, the securing means being arranged to permit a relative shifting 0f the axes of the two nozzles during their attachment to each other; the annular groove being formed upon one of the nozzles and having its edges at the juncture of the said frustro-conical exterior of the liquid nozzle with the said .tapering bore portion of the air nozzle.

3. In a spray nozzle, a liquid nozzle having a small diametered outlet end and a forwardly tapering exterior of generally frustro-conical form behind its tip; an air nozzle having a tapering bore portion fitted upon the tapering exterior of the liquid nozzle and having its frontal bore portion freely surrounding the said tip, the air nozzle also having two diametrically opposite discharge passages leading from its said bore portion to its front, the forward parts of the two discharge passages having their axes intersecting 0n the axis of the said bore portion forwardly of the air nozzle; the said nozzle assembly being provided with connecting passages extending along the said interiitting portions-from the rear end of the said frustro-conical portion of the liquid nozzle substantially to the frontal bore portion of the air nozzle, the nozzle assembly also having an annular groove connecting the said connecting passages with the rear endsof the two discharge passages; and securing means rigidly holding the nozzles in their said intertting relation, the securing means bein arranged to permit a relative shifting of the axes of the two nozzles during their attachment to each other; the said connecting passages comprising last named longitudinal grooves formed 1n the liquid nozzle and extending along the frustro-conical exterior of the nozzle.

4. In a spray nozzle, a liquid nozzle having a small diametered outlet end and a forwardly tapering exterior Vof generally frustro-conical form behind its tip; an air nozzle aving a tapering bore portion fitted upon the tapering exterior of the liquid nozzle and having its frontal bore portion freely surrounding the said tip, the air nozzle also havlng two diametrically opposite discharge portions from the rear end of the said frustro-conlical portion of the liquid'nozzle substantia ly to the frontalI bore portion of the air nozzle,-the nozzle assembly also having' an annular groove connecting the said connecting passages with the rear ends of the two discharge passages; and securing means rigidly holding the nozzles in their said interitting relation, the securing means being `arranged to permit a relative shifting of the axes of the two nozzles during their attachment to each other; the annular groove and the said connecting passages being all of larger cross-section than the forward parts of the diametrically oppositedischarge passages, so as to afford air storage chambers of relatively large capacity behind the said forward passages parts.

5. In a spraynozzle, a liquid nozzle having a small diametered outlet end and a forwardly tapering exterior of generally frustro-conical form behind its tip; an air nozzle having a tapering bore portion fitted upon the tapering exterior of the liquid nozzle and having its frontal bore portion freely l l naamw surrounding the saidy tip, the air nozzle also having two diametrically opposite discharge passages leading from its said bore portion to its front, the forward parts of the two discharge passages having their axes intersectfnecting passageswith the rear ends of the two discharge passages; and securing means rigidly holding the nozzles in their said interfttm relatlon, the securing means being arranged to permit a relative shifting of the axes of the two nozzles during their attachment to each other; the annular groove, the said connecting passages and the rear portions of the diametrically oppositedischarge passages being all of larger transverse section than. the forward discharge passage parts which have their said axes intersecting, so as to cooperate in affording a large storage of air behind the said forward discharge passa e parts.

igned at Chicago, Illinois, December f .MELVINJ-BINKS- 

